O2 customers using the iPhone XR have complained about an issue causing connection problems with the handset.
Users took to Twitter complaining about signal dropping off several times a day, one claiming they have been affected since before Christmas.
O2 is advising handset holders to restart their device to regain service, but warned that signal would only come back temporarily until a solution is rolled out.
Apple is understood to be preparing a fix in a forthcoming software release.
“We’re working closely with our partners to resolve an intermittent issue affecting some of our customers using iPhone XR,” O2 told customers.
“In the meantime, please turn the device off and on to restore the signal temporarily.”
The iPhone XR was released in October 2018.